1. Field of the Invention
The present invention relates to a bridge for supporting the strings of a musical instrument including an instrument body and an acoustic transducer, for example, a diaphragm microphone and an air space chamber which is closed airtight and located in front of the sound receiving side of the transducer.
2. Description of the Related Art
These types of bridges with an integrated sound pickup are used in string instruments, particularly in guitars, electric guitars and basses, mandolins and the like. These bridges are used for amplifying acoustic string instruments without feedback problems as they usually occur in microphones or, for example in electric guitars and bass guitars, for providing a second musical sound variation because several vibration portions of the instrument body are also transmitted by the sound pickup in the bridge.
In accordance with the prior art, bridges which are simultaneously to be used for sound transmission are equipped with piezoceramic elements, as disclosed in U.S. Pat. Nos. 4,160,401 and 4,228,715. In accordance with these patents, a piezoelectric element is arranged either underneath each string or a rod-shaped piezoelectric element is mounted transversely of the direction of the strings between the bridge and the string support which absorbs the vibrations of all strings.
Also to be mentioned in this connection is Austrian Patent 388,071 which shows and describes a bridge with a sound pickup. The sound pickup includes a housing in which a diaphragm microphone is arranged. A closed chamber-like air space or an air gap is located in front of the sound receiving side of the diaphragm microphone. This air space or air gap is bordered at least partially by an elastic and essentially gas-impermeable material. The housing which is open on one side is closed so as to form the chamber-like air space or air space gap by means of a closure which is formed by this elastic material. This elastic material has a preferred density. The sound pickup is arranged in a recess of the bridge.
The previously known constructions described above are only capable of transmitting and converting into an electrical signal vibrations of strings and/or resonating bodies only with great inaccuracy, limited frequency response and limited sound volume range.